Two-blade and cover blind shutter



Feb. 23, 1954 H. L. MALONE ET AL TWO-BLADE AND COVER BLIND SHUTTER Filed Nov. 21, 1952 HAROLD L. MALONE EDGAR S MARV/N IN V EN TOR.

ATTORNEYS Patented Feb. 23, 1954 TWO-BLADE AND COVER BLIND SHUTTER Harold L. Malone and Edgar S. Marvin, Rochester, N. Y., assignors to Eastman Kodak Company, Rochester, N. 35., a corporation of New Jersey Application November 21, 1952, Serial N 0. 321,850

3 Claims.

This invention relates to photography, and more particularly to shutters for photographic cameras.

Shutters now in use on box and other inexpen sive cameras have generally been made as simple as possible, and ordinarily the shutters give a rather fast exposure such as, perhaps, or 5 of a second, because it is less expensive to provide a shutter mechanism for producing such an exposure. For black-and-white negatives with the more recent types of fast films sufficient exposure can be obtained for most lighting conditions. Crude workmanship can be tolerated because strong springs may be used to operate the parts. Where fast exposures are made, there is comparatively little chance to shake a camera during exposure even where the trigger is operated by a strong spring and is somewhat difilcult to depress.

In order to properly expose color films, slower exposures are essential. Usually inexpensive lenses may vary from f/ 12 to f/15 and it is desirable to have an exposure of between & and of a second to properly expose color film with such objectives. It is also desirable to have the shutter made so that it may be operated by relatively light springs and so that only light pressure will be required on the trigger because, with slower exposures, it is an easy matter to shake the camera and spoil the exposure, particularly where considerable pressure is required on the trigger.

One object of our invention is to provide a slow-speed shutter, particularly for the less expensive type of camera. Another object is to provide a shutter in which only light pressure is required on the trigger to actuate the shutter. Another object is to provide a simply constructed shutter which is accurate in that the single selected speed is both relatively slow and can be repeated accurately each time an exposure is made. A still further object of our invention is to provide a shutter in which the exposure has a high degree of uniformity. Still another object of our invention is to provide a shutter of the type in which there are two successively operated blades to make an exposure and a cover blind to insure light-tightness of the shutter blades when closed. Other objects will appear from the following specification, the novel features being particularly pointed out in the claims at the end thereof.

This shutter is for an improvement over the shutter shown in U. S. Patent 2,443,164, Harvey, granted June 8, 1948.

Coming now to the drawings wherein like reference characters denote like parts throughout Fig. l. is a front plan View of a shutter constructed in accordance with and embodying a preferred form of our invention;

Fig. 2 is a fragmentary detail section taken on line 2-2 of Fig. 1;

Fig. 3 is a fragmentary front plan view with the shutter trigger depressed throughout the eater range of its movement and in a position which slight further movement will release the shutter for an exposure;

Figi is a fragmentary detail rear view of the shutter plate showing the cover blind; and

5 a fragmentary section through portions of the trigger and elements cooperating therewith. This section is taken on line 5-5 of Fig. 1.

Qur shutter consists broadly in a mechanism in which there are two shutter blades, one normally open with respect to a shutter aperture, and the other normally closed with respect to the shutter aperture. There is also a cover blind normally closed. with respect to the shutter aperture. When the shutter blades are to be actuated, a shutter trigger is depressed, moving the cover blind from the exposure aperture, then releasing the normally closed shutter blade to open the exposure aperture, this shutter blade setting and releasing a spring which closes the normally opened shutter blade. The successive operation of the two shutter blades is unaffected by the speed of operation of the trigger and results in extremely constant exposures.

More specifically, our shutter may comprise a shutter plate I of the desired shape to fit into a camera or an enclosure for the shutter. This plate 4, in the present instance, is generally rec tangular in shape and is provided with an exposure opening 2. Arms 3 and i extend upwardly from the top edge of the plate to slidably support a trigger 5 which is provided with a pair of slots 8 through which studs may pass. A third arm ll projects upwardly from the shutter plate to support one end 9 of a light coiled spring attached at l l to a flange :2 on the end of the g This tends. to hold the trigger in the normal rest position shown in Fig. 1.

The shutter plate carries a stud l3 on which a normally open shutter blade 14 is mounted so that slot it will. normally lie in such a position as to expose the exposure aperture 2. This blade is of a generally circular'shape having a pair of spaced angular walls iii. These walls may be engaged by the ends ll of a time lever l8 which is 3 fastened to the shutter plate I by a stud I 9 passing through a spring washer 29. Thus, when a pointer 2| points to I, schematically shown at 22, Fig. 1, the shutter is in position for instantaneous exposures and when it points to T the shutter is in position for time exposures.

The shutter blade-I4 is provided with an ofi"- set finger =23 normally resting against. lug 24 formed up from the shutter plate I but capable of moving from this position to a, stop 25 also formed up from the shutter plate I when the shutter blade I4 swings to close the exposure aperture 2. The shutter blade I4 isprovided with a stud 25 around which one end Zlof 'a hairpin spring 28 is looped, the opposite end 129 of this spring being carried by a stud 30 which in turn is carried by the normally closed shutter blade 3|.

Shutter blade 3i is mounted to swing on'aastud 32 carried by the shutterplate I and it includes annpstanding arm 33 and an upstandinglug-M. The-amiss supports the end ofa spring .85 which drives .the'shutter blade .32. 'IIhelug 3.4 forms a catch for the latch element 3.6 pivoted at3'i. to the shutter plateanditis pressed ina generally clockwise direction and into the position shown in Fig. l by means of a spring 38 engaging a flange 39 on the latch. element and a flange it! carried by the shutter. plate I. This bell-crank shaped latch element includes the flange 39 which has .an .additional'iunction of forming an arm against which a flange ll on the lever 32 may strike as willbe hereinafter more fully described. Thelever '42 is pivotally mounted on thev stud 32 and it is bent downwardly at '53 so thatalug to may pass-inwardlyand into a position toengage the edge '45 of the normally closed shutter blade "3| when the parts are in their Fig. 1 position.

The trigger Eincludes apin 41 which, as best shown in Fig. 5, extends in both directions from the trigger 5 and, in the position shown in full lines in Fig. 4, the pin 4? extends forwardly and engages the slot 49 of a cover blind 50 which is preferably also pivoted on the stud 32 and which normally lies over the exposure aperture 2, thus rendering-this aperture light-tight;

With the parts as above describedwithreierence to Fig. 1, pressure on the trigger 5 in the direction shown by the arrow A'causes'th-e trigger to move to'the'right with respect to this figure, moving the cover blind 50 away fromthe aperture 2 during thefirst part 'oithgmovement; A's-the movementcontinuesthe flange H on'the lever 42 strikes the flange 39 ofthe bell crank lever latch membertli, rocking it in 'a counterclockwise direction to release, the latch elements 3.4; '36. This occurs when the triggerris depressed slightly further to the-right than is shown in Fig. '23-, which figure shoWs'the operating flanges ooming'into engagement. *Duringthis-portion of the movement of the trigger from the Fig; l to the Fig. '3' position, spring is-placed under tension because of the clockwise movement of a flange 5! which winds th spring in a clockwise direction. When the latch elements 34, 35 become disengaged, the normally closed shutter blade 3! swings in a clockwise direction, thereby uncovering the exposure aperture 2 as the edge 53 of the cover blind crosses the aperture 2.

At this, instant, the exposure through aperture '2 lustartedbecause the slot S5. in the cover blade Itislying across the exposure 'aperturez. However, as theihairpin springzfl is tensionedby the studi3llswinging in a clockwise. direction, it will continue to be tensioned more and more until the stud 38 passes between the studs 32 and 26 at which time the hairpin spring will be completely tensioned so that it may be finally released, causing the normally closed shutter blade I4 to swing in a counterclockwise direction while the stop 23 moves from the lug 24 to the lug 25, at which latter position the exposure aperture, is again closed.

When the exposure has been completed, pressure is released on the trigger 5 and the spring ID will return thetrigger to its Fig. 1 position. This movement releasessome of the pressure from the drive spring ,and at the same tim causes the lug '44 to engage the shutter blade 3| so that it will be movedby lever t2 back to its Fig. 1 posit on. As thismovement takes place, the hairpin spring 28 is again tensioned and released, this time in "an opposite direction, as the stud 30 swings back to its Fig. 1 position but, before movement .of the shutter blade M occurs, the coverlblindi'et will have been moved a sufficient distance to cover the exposure apertureZ so that no light may enter during the resetting :move ment of "the shutter'blades 3i and M. The-shutter blade I3 will'be moved'to re engagethela'tch elements it and 36 so that the neXt'cycle'ca-nitake place.

If time exposures are required, the lever-1 8 may be swung in a clockwise direction with-respectito .1 so that the pointer 2 I 'willpoint to KIT-7, the angularly disposed walls it of the shutter blade i l and, consequently, this shutter blade will ermeable to move, even though the hairpin spring 23 is 'tensioned and released as shutter blade 3! swings to its open position when iihe trigger is actuated. Therefore, since the cover blind -56 and the shutter blade 3! are-opened by pressure on the trigger, and since shutterblade I' l is'already open, an exposure will be made-and will'be terminated when the trigger *5 is released to return with the shutter blade "31 and cover blindiib to'its initial or Fig. 1 position.

While the described construction shows apreferred embodiment of our invention which is well adapted for-practical use, it should be pointed out that this construction permits extremely light-- weight springs to be employed. The hairpin spring 25 is made of extremely lightweightmaterial which can readily be 'tensioned and -releasedby the action oi the sp ing in-opening the shutter blade 3! The spring 35 is onlysiunder relatively light tension in its rest position, shown in "Fig. .1, but it is wound up to a limited extent by the operation of the lever 32 whenthisgilevnl is moved :bymeans oi the trigger 5 .throughjthc pin llr'l. Thus, spring '35 only to be heavy enough to iust overcome the tension ofzthehairpin spring and to dri e theshutter blade Strand, since there are onlythesetwo light springsitoabe overcome by the spring this spring alsa-mav be-madecomparatively light so that sthe ipressure on the trigger A need not begreat and :so. that the shutter can be released by light pressure. The spring 58 holding the latch element 36 in its operative position is likewise a comparatively light spring asthe sole functionof ithis'springzis to "hold the latch '38 in a positionxtoiengagethe latch element 3 d when the shutter blade 31 moves to its closed position. A stop 56 may be provided on the shutter plate to-limiti-the clook wise movement of the bell crank latch element 36 under the-influence of, spring 38.

Having thus described ourinvention, what we This will cause the s'toparm I-'I to engage claim is new and desire to secure by Letters Patent of the United States is:

1. A camera shutter comprising an apertured supporting plate, a movable trigger, a first lever pivotally mounted on one side of the plate, a second lever pivotally mounted on the other side of the plate, interengaging elements on each of the levers and the trigger for operating the levers by the trigger, a spring tending to move the trigger to a rest position, the first lever including an aperture covering portion and constituting a cover blind, the second lever carrying a lug, a first pivoted shutter blade having a rest position covering the exposure aperture and having a latch element thereon, and movable from its rest position to uncover the exposure aperture, a second pivoted shutter blade having a rest position exposing the exposure aperture and movable therefrom to cover the exposure aperture, a hairpin spring connecting the first and second shutter blades to drive the latter by the former, a spring between the second lever and the first shutter blade for driving the latter by the former, a latch element pivotally mounted on the plate and positioned to engage the latch element of the first shutter blade in its position of rest, means on the second lever for engaging and releasing the latch element, said spring between the second lever and the first shutter blade being tensioned as the lever moves to release the latch element, the normally closed shutter blade when released moving to tension the hairpin spring connecting it to the normally open shutter blade to tension and finally release said hairpin spring whereby the normally open blade may move to close the exposure aperture completing an exposure.

2. The shutter construction defined in claim 1, characterized in that the pivoted shutter blind lies in substantial contact with the supporting plate and in that the normally closed shutter blind is spaced therefrom whereby the latter may turn freely about its pivot.

3. A camera shutter comprising an apertured supporting plate, a movable trigger, a first lever pivotally mounted on one side of the plate, a second lever pivotally mounted on the other side of the plate, the two pivotally mounted levers being coaxially pivoted, interengaging elements on each of the levers and the trigger comprising pins and slots for operating the levers by the trigger, a spring tending to move the trigger to a rest position, the first lever including an aperture covering portion and constituting a cover blind, the second lever carrying a lug, a first pivoted shutter blade having a rest position c0vering the exposure aperture and having a latch element thereon, and movable from its rest position to uncover the exposure aperture, a second pivoted shutter blade having a rest position exposing the exposure aperture and movable ther from to cover the exposure aperture, a hairpin spring connecting the first and second shutter blades to drive the latter by the form r, a spring between the second lever and the first shutter blade for driving the latter by the former, a latch element pivotally mounted on the plate and positioned to engage the latch element or" the first shutter blade in its position of rest, means on the second lever for engaging and releasing the latch element, said spring between the second lever and the first shutter blade being tensioned as the lever moves to release the latch element, the normally closed shutter blade when released moving to tension the hairpin spring connecting it to the normally open shutter blade to tension and finally release said hairpin spring whereby the normally open blade may move to close the exposure aperture completing an exposure.

HAROLD L. MALONE. EDGAR S. MARVIN.

No references cited. 

